- Introduction 2:03
- Creating a Route 4:45
- Creating a Route 4 questions
- Viewing Routes 1 objective
- Adding a Route 1 objective
- Creating a Controller 2:39
- Creating a Controller 1 objective
- Creating a View 1:29
- Creating a View 1 question
- Creating a Model 3:32
- Creating a Model 1 objective
- Adding Records via Rails Console 3:17
- Populating the View 8:57
- Populating the View 2 objectives
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Creating a Route
4:45Rails lets you set up "routes" for requests, so that you can send a particular request to a controller that can handle it.
A given Rails app is likely to
have a whole bunch of resources,
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each with its own controller
to handle requests for them.
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In our Blog app requests to create,
read, update and
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delete posts are handled
by the PostController.
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Now we need to add a PagesController
to handle current requests for pages.
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But how will the requests
get to the PagesController?
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How do we tell a request for
a post apart from a request for a page?
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Rails lets you set up routes for requests.
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So that you can send a particular request
to a controller that can handle it.
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We'll look at how to set up routes next.
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We're here in our Blog app
viewing the /post path.
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It displays a list of all
our post model objects.
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In this stage, we're gonna set up
a list of all our page model objects.
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We're going to want that list to
be available at the /pages path.
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But let's see what happens if
we try to visit that path now.
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We'll change /post here
in the URL bar to /pages.
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We see an error.
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No route matches get /pages.
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So what's this route it's referring to?
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Your Rails app has several controllers,
each with several actions methods.
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When Rails receives
a request from a browser,
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it needs to know which
controller action to send it to.
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To determine that, it looks at
the http request type and the path.
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Remember, that's the part of the URL
following the server and port.
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Then Rails looks for
a route to determine which controller and
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which method should handle that request.
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So you might have a route that says,
get requests for
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the /pages path should be sent to
the PagesController's index method.
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Whenever Rails receives a get request for
/pages,
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it'll call the index method
on the PagesController.
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You can get a list of all the routes
in a Rails app from your Terminal.
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Stop the server if it's running,
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and type bin/rails routes.
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Windows users, don't forget to type
ruby bin\rails instead of bin/rails.
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There are lots of routes for post
resources but none for page resources.
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We're going to need to have one.
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A Rails application's routes are
configured within the config directory.
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In the routes.rb file.
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This file contains Ruby code
that sets up the routes.
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The syntax can be a little confusing,
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especially if you're not used to
keyword arguments on Ruby methods.
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Don't worry about fully
understanding it right now.
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If you copy the examples we show you
here you'll be able to modify them
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to suit your needs.
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Let's add a route for the /pages path now.
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Remember, there are several types of
HTTP requests, such as get and post.
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When your browser sends a request
to view a page, it's a get request.
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So we'll call the get method
to set up a get route.
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As an argument to the get method,
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we need to provide the path that
this route should match as a string.
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So we'll start a string and type /pages.
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The next argument to
the get method is a hash,
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where you can specify keys and
values with various options.
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One of those is the to key,
which specifies which controller and
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which action method that
request should be sent to.
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So we type a key of to, and
the value should be a string.
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The first part of the string is
the name of the controller we want,
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with the word controller left off for
brevity.
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We want our requests to go to the
PagesController, so we'll type pages here.
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The second part of the string
specifies which of the controller's
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action methods should handle the request.
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In Ruby documentation, instance methods
of a class are marked with a hash mark,
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and the same convention is followed here.
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So type a hash mark, and
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then the name of the action method we
want to be called, which is index.
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In plain English you could read this as,
get requests for
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the /pages path should go to
the PagesController's index method.
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If you go back to the Terminal now and
run bin/rails routes again,
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you'll see a new route
on the end of the list.
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It directs get requests for
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the /pages path to
the PagesController's index method.
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Now that we have a route, let's try
visiting the /pages path again, and
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see if the routing error goes away.
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In case you're tired of typing
Rails server all the time,
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let me give you a preview
of a handy shortcut.
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You can just type the letter
s in place of server, so
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we'll run bin/rails s
to launch our server.
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Now we'll reload our page, and
the original error is gone.
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Rails sees the request for
these /pages path and
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tries to route it to the PagesController.
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But that controller doesn't exist yet.
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So instead we see the error
uninitialized constant PagesController.
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We'll fix that problem next.
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By the way, if you wanna read
more about get routes in Rails,
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be sure to check the teacher's notes.
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